Process and apparatus for making floating soap



Jan. 17, 1950 D. E. MARSHALL 2,494,891

PROCESS AND APPARATUS FOR MAKING FLQATING SOAP Filed May 2, 1945 2Sheets-Sheet l INVENTOR v z, 772M ATTORNEY Jan. 17, 1950 MARSHALL2,494,891

PROCESS AND APPARATUS FOR MAKING FLOATING SOAP Filed May 2, 1945 2Sheets-Sheet 2 Hm- 1 A llmnl. x2; 1

| 1 M III I i N w g v n m m i "r M m a w I an N 1 N l QUORNEY PatentedJan. 17, 1950 PROCESS AND APPARATUS FOR MAKING FLOATING SOAP Donald E.Marshall, Summit, N. J., assignor to Colgate-Palmolive-Peet Company, acorporation of Delaware Application May 2, 1945, Serial No. 591,553

14 Claims. 1

This invention relates to an important improvement in soap manufacture.With this invention floating toilet soap is produced that has textureand plastic characteristics that have been present heretofore only infine hard-milled soaps.

Soap finishing processes can be compared to I candy making to explainthe importance of crystal formation. A hard-milled soap is like a smoothcreamy fudge. Hot framed floating soaps, or, to a somewhat lesserextent, the new forms of hot mixed and quick-cooled low moisture float-,ing soaps are like a sugary fudge. In both known in the trade ashard-milled soap, and

scientifically as Beta phase crystal structure.

- When a plasticized, milled textured soap mass is overheated, itreverts to a, hard crystal structure and loses much that has been gainedby milling.

,The conventional-way of incorporating air in low-moisture, floatingsoaps is by working air into the soap while it is heated above a pointwhere it is fluid enough to beat and then, in some instances, quicklycooling while it is still being mixed. This does not produce the desiredresults of good water-cooled milling of the present invention, butyields a different soap structure which is not like the present moldableplastic milled soap which, because of its crystalline structure, cannotbe stamped into toilet soap tablet shapes.

With the present invention smooth, plastic textured ribbons are takenfrom the conventional milling process and are passed through a specialmulti-barreled, water-cooled plodder in such a manner that finelydivided bubbles of air are incorporated in the soap without working orbeating the soap mass materially. In this way the crystalline structurethat would result from overheating is avoided.

In carrying out this invention a milled soap mass is plodded andextruded into very fine threads of, say about 0.030" diameter without Imaterially elevating its temperature, and a measured, though very smallamount of air is introduced within this finely Shredded soap mass. Thenwhile the soap is kept under regulated air pressure, the shredded soapmass is compacted progressively so as to become hard Without allowingthe escape of the occluded air.

The stages of successive shredding, aerating and compacting are repeatedone or more times to provide uniformity. Then the aerated mass of soapis extruded through a nozzle and a sizing plate to obtain thecross-section that is desired for the out bar, preliminary to stamping.

In carrying out the process, the soap is repeatedly shredded, aeratedand compacted under moderate air pressure, and the air is not allowed toescape at any step, until the air is uniformly dispersed and locked intothe milled soap mass, without materially elevating the temperature ofthe soap. Overheating is avoided by the minimized working of the soapmass and by utilizing water-cooling to dissipate the heat of frictionalong the plodder barrel and worm.

It is well known in this art that the process of de-aeration consists ofreducing a liquid cream or plastic material to be de-aerated to a finelydivided form and then subjecting the finely divided material to avacuum.

With the present invention air is occluded in soap by adapting thisprocedure of first reducing the plastic soap mass to threads, and theninjecting air into the threads and slowly compacting the same under airpressure.

In carrying out the present invention for manufacturing milled floatingsoap, conventional :practices are used for processing the soap up to theplodder stage. With such processes kettle soap is passed over chillingrolls to congeal and deliver the soap in ribbons onto a screen conveyorof a drying oven where moisture is removed under moderate heat andventilation, so that the flakes are dried as uniformly as possible to amoisture content of approximately 10-18%, depending on the quality ofthe finished bar desired. The dried flakes are then mixed with thedesired perfume and preservatives and milled to an extensive de- 7 gre'eand at reduced temperatures.

The extensive. milling to which I refer is obtained by passing the flakemixture through two sets of Lehman #916 5-roll steel mills in tandem,set closely and so as to get good coverage and yet deliver only3,000#-3,300 pounds per hour of milled ribbons. Also, I prefer to keepthe cooling water so that the ribbons are maintained at roomtemperaturesapproximately F. All of this is conventional practice wherehigh quality fine textured hard-milled toilet soap is manufactured, butparticular emphasis is placed on the temperatures necessary to get themicro-crystalline amorphous texture desired.

These milled ribbons are then fed to an aerating plodder, in accordancewith this invention in which Fig. 1 is a longitudinal view partly insection through an illustrated embodiment of the invention, parts beingshown diagrammatically;

Fig. 2 is a broken-away section of Fig. 1 shown on a larger scale;

Fig. 3 is a section along the line3-3 or Fig.2?

Fig. 4 is a section on a large scale along. the line 4-4 of Fig. 3.

In the drawings, reference .ch'aractenl indicates a screw that isrevolubly located in the barrel 2 of a plodding machine that is providedwith a feed opening 3. A cooling jacket 4 surrounds the barrel 2 andfins 5 are provided in this jacket:'

A drive shaft 6 is attached to the worm I and a pulley 1 is provided onthe shaft. A compressed air supply 9 is provided withair-lines|0,"a'calibrated orifice ill, a-manometer ll, gauges l2 and valves l3and suppli'escompressedair in regulatedamounts as indicated.

A longitudinal central opening H isprovided in=the-worm i and aninlettub'e 'for the compressedair with a proper gland is connected totheouter'end. Acomminuting head 16 (Fig; 3) is connected by pins 11"(Fig. 2) so as to revolve with the worm I. Radial channels I! areprovided -in the head- [Wand communicate with axially-extendingbranches'lfii These channels als'o communicate with the central openingM through portsd 4 1' The channels lfl extend inside of: the comminutingblades-20 and 2| of the" head 16.

A'foraminous plate ZZKFi'g; 2)- with numerous small. holes 23theret-hroughi is anchored by clamping rings 24 which holditin closeproximity to the'headlt. A thick pressure plate which serves asabackingfor the-plate 22 is provi'ded. It is anchored in-contact withthis plate'.- Conicall'yeshaped :openings 25 extend transversely throughthe pressureIplate ZS; Cutter blades 21 which are attached soas torevolve with the-"- screw"! are'inconta'ctnwith the outerside of thepressureplate 25. A -studscrewz281and spring 29 areprovided tokeepatheblades 21. resiliently in place.

Thepassageway provided-"by ansairtight removable-closure-30a extendsfrom the exit: end of the first plodder to azsecond-stage plodder thatis like it. Corresponding parts of this plodderz-are referred to by the'same reference characters with primes, as used above; A passageway 3|also provided by an airtight removable-closure 302a leads-from the=exitend of'thesecond stage plodder tothebarrel 32 that is. providedwithaworm. 1a.

At the outlet of .barrel 32 a convergingsection' 33 is. provided withasizingand shaping outlet 34 having an.orifice 33 that. is shapedinsucha manner that the cross-sectionof the-soapthat is extruded therethroughhas the desiredshape and size. Reference character 35 indicates aheaterat the end of section 33.

Reference character 36 indicates tubes for circulating coolihgwater incontact with the fins 5, 5 and 5a to keep the soaprthat is beingtreatedat the proper temperature.

The enlarged partly broken away detail, Fig. 4, shows .how the blades 20of the comminuting wheel 16 wipe the soap and air that is introducedthrough channels. is through holes 23. The blades 2! scrape the platesurrounding these openings clean. This Fig. 4 also shows how theextruded threads 38 of soap are compacted gradually as they pass throughthe tapered holes 26 of the pressure plate 25. This figure also showshow the threads become integrated before they emerge and are cut oif ascompacted pellets by the. blades 21.

Glands 40 are provided 'on the worm shafts I, i and la to prevent theescape of air.

In carrying out this process the milled soap ribbms produced'asdescribed above are fed to the first plodder stage through opening 3 andare compacted by worm i into a solid soap mass and the pressuredeveloped in forcing the soap through. the pressure plate 25 effectivelyseals the space between Worm l and barrel 2 so as toprevent-backwardescape of air that is introduced through the comminutinghead l6. This head l6 works the soap mass through the foraminous plate22,.which is provided with holes or openings 23'(Fig'. 4), assisted bythe pressure developed by "theworrn I. The'blades ZO'are soinclined thatthe soapunass ispositively forced through the openings 23. At the sametime air entering through'branches I9 is pocketed as small bubbles intheisoap threads. The-exits of the-air orifices are oiiset so that bubblesoi air are entrained with'the flowing soap;-

The edges of the blades 2i are at right angles to the plate 22 sothatthe surface of this plate is scraped'clean or obstructions as veryfrequent intervals. Also, air is introducedat the trailing edges ofthese blades 2 I- so astodistribute theair more evenlyjin' the soap mas.In" order toobtain a uniformly textured'soap; the *plate- 22 should haveabout 300'to400holes per'square-inch and this plate is about 18 gaugemetal.

The extruded andaerated-threads leaving the holes 231pass into the'conical openings 26 in the "pressure plate 25"where this restriction is"sumcient to compact the aerated threads into pellets. The pressure inexit chamber Mia-is suflicient to prevent de-aerationoi these pellets.

In order 'to' aeratethe soap" to the degree of fineness desired," one ormore additional aerating stagesmay be utilized as indicated by barrel 2'andworm. I" whlchoperate. similarly to the precedingwone. However, inthis stage the feed is already under pressure and leakage near the shaftis prevented by packed gland '40.

When the'aerated Isoap; which'is still held under..the desiredpressure,enters the final plodding stage'it' isgradually compressed by the wormla which is shaped so as to compress the soap sufiicientlyjso that.Lwhenithe mass reaches the exit 'end.it is well. compacted and isextruded as a homogenousstream which is free from cracks or striations.The. soap thenhas a structurethat retains the exceedingly fine particlesof air, even though a certain amount of expan sion takes placeas thesoap stream leaves. the orifice plate33.

Witlrthis' multi-stage. Dlodder the soap mass is processedwithoutheating the soap materially since the soapispreferably kept at atemperature below- F. duringv the plodding .and aerating operation.

The floating, milled soap. produced by this process, possesses most ofthe qualities imparted by low-temperature hard-milling; it can bestamped or molded into tablet shapes, and in addition .possesses thequick solubility and white color of high quality floating soaps.

With'this inventionsoap is compacted around (Ismail air particlesinstead 'of air particles being beaten into the soap mass. The resultingproduct is an extruded uniformly aerated soap that has not been heatedenough to make it sticky. Therefore it can be immediately cut andstamped after it has been produced without any need of further drying orcooling.

While this invention is particularly described in connection with makinga low moisture floating soap, it is obvious that it can be used indifierent ways. For example, it may be used to produce a high moisture,say between 18% and 30% floating soap that has not been milled nor driedto milled soap water content, by extruding chilled ribbons of such soapand by omitting most or all of the drying and all of the millingoperation. Also, an

aerated laundry bar formulated in the usual manner using "builders" andhaving a moisture content of between 18 and 42 per cent can be extrudedfrom chilled ribbons of such soap by omitting most or all of the dryingand all milling operation. In the latter case the resulting soap may notfloat but the aeration increases the size of the bar and produces adesirable texture.

In the case of built laundry soap the ingredients must be strainedthrough a very fine screen before chilling so as to avoid stopping theholes in the plodder plate 22.

In some cases of formulas containing over 18% moisture it may benecessary to skin dry the extruded and cut soap before stamping.

What is claimed is:

1. In an apparatus for homogenizing, compacting and extruding a materialsuch as soap, the combination which comprises a plodder having a barreland a worm operating in the barrel for compacting and feeding forward amaterial supplied to the plodder, a comminuting head located at the endof the worm for spreading the material being fed forward by the worm, adrive for said comminuting head, a foraminous plate located behind thecomminuting head and upon which the material is spread and then forcedthrough by said comminuting head, means located at the comminuting headfor injecting a compatible gas into the material as said material isspread on and forced through the foraminous plate whereby particles ofthe gas are incorporated in and uniformly distributed throughout thmaterial.

2. An apparatus as defined in claim 1, including mechanical compactingand extruding means for integrating the material discharged from theforaminous plate under mechanical pressure, a sealed, pressurizedchamber connecting said lastmentioned compacting means with thedischarge side of the foraminous plate and means for supplying a gas tosaid pressurized chamber whereby the material being compacted may bemaintained under pressure to prevent the escape of the gas particlesincorporated in the material due to the mechanical pressures ofcompacting and extruding the material.

3. An apparatus for homogenizing, compacting and extruding a materialsuch as soap, which comprises the combination of a plodder having abarrel and a worm operating in the barrel for compacting and feedingforward a material supplied to the plodder, a comminuting head includinga radially extending blade located at the end of said worm forprogressively spreading the material being fed forward by the worm, adrive for said comminuting head and a foraminous plate located behindthe comminuting head and upon which the material is spread and forcedthrough by the blade of the comminuting head, said blade having outletports connected to a supply of gas along one face thereof for' injectinga gas into the material spread on and forced through the foraminousplate whereby particles of the gas are incorporated in and distributedthroughout the material.

4. An apparatus for homogenizing, compacting and extruding a materialsuch as soap, which comprises the combination of a plodder having abarrel and a worm operating in the barrel for compacting and feedingforward a material supplied to the plodder, a comminuting head includinga radially extending blade located at the end of said worm forprogressively spreading the material being fed forward by the worm, adrive for said comminuting head and a foraminous plate located behindthe comminuting head and upon which the material is spread and forcedthrough by the blade of the comminuting head, said blade having outletports connected to a supply of gas along one face thereof for injectinga gas into the material spread on and forced through the foraminousplate whereby particles of the gas are incorporated in and distributedthroughout the material, a mechanical compacting and extruding means forintegrating the material discharged from the foraminous plate undermechanical pressure and a sealed chamber connecting said mechanicalcompacting means with the discharge side of the foraminous plate, saidchamber being connected to a supply of gas under pressure formaintaining a gas pressure in said chamber to prevent escape of theparticles of gas incorporated in the material under the pressures oftheme-- chanical compacting.

5. An apparatus as defined in claim 4 including a cutter located on thedischarge side of the foraminous plate and a drive for said cutter.

6. An apparatus for aerating and extruding a material such as soapwithout beating or appreciably working the mass of said material,comprising an extrusion Worm operating in a plodder barrel for initiallycompacting and feeding a particulated material, a comminuting headassociated with said worm for moving compacted material across theopenings in a foraminous plate and to spread said material and force itinto said openings, a gas-introducing means for causing gasto beintroduced into said openings together with said material wherebyparticles of the gas are enveloped by said material forming aeratedshreds of the material being forced through openings in said foraminousplate, a sealed chamber for receiving the aerated material passingthrough said foraminous plate, means for mechanically compacting andextruding said aerated material and means for maintaining gas pressurein said sealed chamber for preventing escape of the gas cells under themechanical pressure of compacting and extruding said material.

7. An apparatus as defined in claim 6, wherein said gas is introducedthrough openings in the blades of said comminuting head so as to beentrained with the materials in the openings of said foraminous plate.

8. Apparatus for aerating and compacting a material such as soap whichcomprises a plodder having a barrel and a worm operating in the barrelfor compacting and feeding forward a material supplied to the plodder, aforaminous plate at the end of the worm, a comminuting head rotatablewith said worm including alternate spreading blades and cleaning blades,each spreading blade having a forwardly inclined leading face operatingto progressively spread the material being fed forward by the worm overthe fcraminous :plate and force the same therethrough and having gassupply passages with outlet ports on saidzinclined leading face forinjecting gas into the material spread on and forced through theforaminous plate, and said cleaning blades operating to scrape thesurface of the foraminous plate clean and having gas supply passageswith outlet ports on the trailing side thereof for distribution of gasin th soap mass, whereby particles of gas are incorporated in anddistributed through the material.

9. A process for aerating milled soap, comprisin: the steps ofcontinuously compacting unheated milled soap chips and progressivelyfeeding said compacted soap chips forward, shredding and aeratingthesoap by forcing the compacted soap through openings in a foraminousplate extending across the direction of flow of said soap and forcingparticles of gas with th soap through said openings whereby theparticles of gas are envelopcd by said soap to form aerated shreds ofsaidsoap, maintaining gas pressure on the gas containing soap shredsleaving said plate to retain cccludedgas, and then mechanicallycompacting said shreds into bars of aerated milled soap which float,said process being carried out while maintaining the soapin solidifiedcondition.

10. Theprocess of claim 9, wherein said aerated shreds are mechanicallycompacted under gas pressure, said gas pressure opposing the escape ofgas cells from said aerated shreds due to said mechanicalcompactinguntil a suflicient mass of said shreds is integrated to prevent suchescape,

and then extruding the soap as uniformily aeratedmilled soap whichfloats.

11. The process of claim 9, wherein the temperatureof the unheatedmilled soap chips is kept below 80 F. during the shredding and aeratingwhereby the aerated soap retains the micro-crystalline state andcompactness of a hard milled S039.

12. The process for continuously producing an aerated soap having thecompactness and crystalline structure of a milled soap which comprisesthe steps "of progressively compacting milled soap flakes into a massand feeding the compacted soap mass forward, then shredding the soapmass while maintaining the soap in solidified condition by progressivelyspreading the compacted soap mass on a foraminous plate, forcing itthrough the openings in said foraminous plate to form threads or shredswhile simultaneously supplying a gas to and occludingiparticles of gasin the soap threads or shreds, and mechanically compacting and extrudingthe soap threads or shreds with particles of gas occluded therein whilemaintaining the soap under a gas pressur sufficient to prevent escape ofthe gas particles from the compacted mass due to the pressure of saidmechanical compacting.

13. The process of continuously producing an aerated soap whichcomprises compacting a soap stock into a uniform mass while feeding thecompacted mass progressively forward, shredding said compacted mass ofsoap stock by progressively forcing the soap stock through a foraminousplate while maintaining the soap stock in solidified condition andsupplyinga gas thereto adjacent to said foraminous plate and prior topassage therethrough, whereby a gasis passed through said foraminousplate with the soap to incorporate and uniformly distribute particles ofgas in the soap i shreds, then mechanically compacting the comminutedand aerated soapshreds into 'a uniform. integrated mass whilemaintaining the soap under a gas pressure sufficient to prevent escapedue to the mechanical pressures of the compacting of the occluded gasparticles and then extruding said mass through a discharge orifice.

14. The process as defined in claim 13 wherein the aerated soap mass iscut and formed into finished bars as it is extruded.

DONALD E. MARSHALL.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,048,286 Pease July 21, 19362,210,924 Hood Aug. 13, 1940 2,295,594 Mills Sept. 15, 1942 2,377,424Ittner June 5, 1945 2,398,776 Bodman s Apr. 23, 1946

